Which of the following is a characteristic of socialism?
I do guess C
None of them, except maybe the first. Most means of production in the warsaw-pact countries were owned by the government and a lot was planned centrally, but that isn't specifically socialist. Socialism is a type of economy in which you get paid according to your (own) work. The means of production are to be owned by the workers/people or their local collectives, and operated to fulfill the needs of the people rather than to compete other collectives out of existence or maximise profit. Getting paid according to your work in the warsaw-pact meant that miners got more wages per hour than doctors. None of those countries had a shortage of people wanting to become doctors